Apparatus for pressing articles from ceramic materials



30, 1932- M. MICHEL ,87

APPARATUS FOR PRESSING ARTICLES FROM CERAMIC MATERIALS Filed Nov. 21. 1930 3Sheets-Sheet 1 Fig.2

Juvenfor' MAX- M ICHEL QWN fifformey M. MICHEL APPARATUS FOR PRESSING ARTICLES FROM CERAMIC MATERIALS Filed Nov,- 21, 1930 5 Sheets-Sheet 2 Unvenfor MAX M 2 CHEL. Q i fforrzeg Aug. 30, 1932. M. MICHEL 1,875,475

APPARATUS FOR PRESSING ARTICLES FROM CERAMIC MATERIALS Filed Nov. 21,1950 3 sheets-sheet 5 Javebfor MAX M ICHEL.

Patented Aug. 30, 1932 UNITED STATES PATENT OFFICE MAX MICHEL, OF FREIBERG, GERMANY, ASSIGNOR TO EOBZELLANFABRIK KAHL ZWEIGNIEDERLASSUNG FREIBERG, F FREIBERG, GERMANY APPARATUS FOR PRESSING ARTICLES FROM CERAMIC MATERIALS Application filed November 21, ISBO SerialNO.

My invention relates to a process ofmolding or pressing artlcles from a ceramic material and to a mold for carrying out such process.

in'g' proper.

. pressing process to pass through an operation similar to that which is effected in molding rotating bodies with the molding wheel. The

its diflerent portions.

.tained to the desired extent.

If articles produced from plastic and particularly ceramic masses are not to be liable to distortion or breakage during baking or drying it is necessary that their mass shall be homogeneous and that no divergent ten- ,sions in the masses should be present. In 10' order to attain this object, it is customary to subject ceramic masses to be molded on a lathe or otherwise to a preparatory manual rotary kneading treatment prior to the mold- In the process of pressing articles from relatively large ceramic bodies, however, the homogenizing and the equalization of the tensional stresses offer particular difliculties since the pressure exerted on the material inthe mold will destroy the preceding homogenization or a previously established equalization of the tensions. This is due to the fact that during compression the mass is moved radially to thecentre of the matrix and consequently becomes unequal in Nor does the rotation of matrix and pressure die relatively to one another offer a remedy as by this method also a thorough kneading of the mass is not at- Particularly ditficul't is the pressing of bodies with highly profiled surfaces as the curves and projections are apt to enhance the inequalities of the mass.

The object of my invention is to overcome these disadvantages.

I have found that superior results are obtained by causing the'material during the mass is therefore firmly kneaded during the molding by the pressure tool and consequently homogenized as well as freed from obnoxious .tensions.

To this end the pressure die and the matrix which constitute the mold and during the pressing process perform a rotary movement relatively to one another, are provided either b th or individually with one or several way "spirals or spiral shaped kneading projections.

and will move the mass-spirally from 497,318, and in Germany November 22, 1929.

These spirals knead the mass during the pressing operation and force it'to move along spiral paths instead of in radial directions thereby effecting a homogenization of the structional examples of rotary'molding tools for carrying out my novel process are illus trated in which I have arranged spirals on the pressure die. In the dies shown the spiral kneading projections are in one plane but they could be arranged also on dies or matrices, the basic shapes of which are curved, oblique or vertical or terminate in shapes which are a combination thereof.

Figs. 1, 4 and 7 are aplan view on the internal face of the die or upper mold section,

Figs. 2, 5 and 8 illustrate a diametrical section through the die shown in Figs. 1, 4:,

or 7 respectively, and

Figs. 3, 6 and 9 represent the matrices including the molded ceramic bodies which are adapted to cooperate with the dies shown in the other figures.

The die a is carried by a suitable machine (not shown) similar to a boring machine which imparts a rotation to the die about its axis and at the same time permits the operator to lower the die on and into the stationary mold 7 arranged on a suitable support and charged with the requisite quantity of the ceramic material, e. g. porcelaine mass indicated at c. I

Figs. 1 and 2 show a die or mold section provided with spiral shaped projections b which rotates in the direct-ion of the arrow 6 inward to outward along the line (i.

In the tools shown in Figs. 4, 5 and 6 the kneading spirals b are such as to cause the flow of the mass in the direction of the arrow at from outward to inward. The tool itself rotating in the direction of the arrow 6. The matrix) is again charged with the mass and may be so sha ed that its edges project above the molded o ject 0. For the purpose of discharging the excess of substance, the molding tool a is provided with a central boreg, by way of which the mass may escape in the direction of the arrow k. The innermost kneading spiral bis extended into the centre of the bore 9.

With forms of the 1 pressed body other than those shown itmay be desirable for the purpose of removing the excess, of substance to provide several bores 9. These bores may be arranged either centrally or eccentrically and may be either in the pressure die or in the matrix orlin both.

According to Figs. 7, 8 and 9 which show a tool with a two-way s iral b, the central bore 9 in the pressure ie is used for the introduction of the mass in the direction of the arrow h, the spirals 6 during rotation of the tool. a moving themass from inward to outward in the direction of. The matrix I accordingto Fig. 9 need in this case not be charged with the mass 0. In this. arrangement the kneading spirals terminate centrally in'the web 2 which bridges. the .central openin for the purpose of attaining a smooth sur ace on the article a. As regards the number and place of the bores in the die and in the matrix the same applies as stated in the preceding paragraph.

The supply or removal ofthe mass by Way of bores in the die or matrix prevents the occurrence of pressures in the mass which counteract the kneading of the mass by the spiral shaped projections. These bores are therefore of particular importance when used in dies or matrices with kneading spirals.

For pressed objects which are toreceive a profiled surface the kneading spirals must be shaped accordin to the relief and sunk portions of the sur ace.

What I claim is 1. Apparatus for forming articles from a ceramic material consisting of relatively rotatable sections in which at least one of said sections is formed with a spiral shaped kneading projection and provided with a boring for feeding material to or from the apparatus.

bodies rom plastic material, comprising relatively rotatable die and matrix members,

a plurality of disconnected ridges on one of said members, said ridges being spiral, the

.inner. sides of each ridge being defined by a 2. Apparatus for forming homogeneous crease in a direction counter to the direction of rotation.

I 3. Apparatus for forming homogeneous bodies from ceramic material, comprising a stationary matrix, a die member rotatable with respect to said matrix, said die member ture.

MAX MICHEL. 

